Espresso basics: dose, ratio, time

Espresso is the least forgiving method in this site's catalog, but its recipe is also the most precisely published. Two official anchors cover almost everything a home brewer needs: illy's preparation guide gives the classic Italian spec, and Counter Culture's brew guides give the modern specialty recipe. Between them sits a simple framework — dose, ratio, time — that turns "my shots are bad" into a solvable problem.

The numbers up front

Sources, fetched 2026-11-16 (nofollow): illy FAQ (7 g, temperature, 25–30 s) · illy Espresso Preparation Guide (professional PDF, illy.com) · Counter Culture Quick + Easy Espresso.

Dose: the fixed point

Dose is how much ground coffee goes in the basket, and it's mostly decided by your basket, not your taste: baskets are engineered around a fill height, and over- or under-dosing causes channeling long before it changes strength. Start at 18 g for a standard double basket (16–20 g depending on depth) and leave it alone. illy's 7 g figure describes traditional single baskets; singles are harder to extract evenly and most home grinders can't dial two doses at once, which is why the modern recipe just doubles everything.

Ratio: the strength dial

Espresso ratio is yield weight ÷ dose weight. An 18 g dose pulled to 36 g is 1:2 — the standard starting point; 27 g would be 1:1.5, a shorter, heavier, more intense shot; 45 g would be 1:2.5, longer and more tea-like. Counter Culture publishes that whole window as legitimate. The habit that separates good home espresso from frustrating home espresso is weighing the yield: put your cup on the scale, tare it, and stop the shot at the target gram weight rather than watching for color. Volume lies — crema is mostly gas, and dark roasts make inches of it. For conversions and the underlying arithmetic, the espresso preset in our ratio calculator shows exactly how the 36 g yield splits per shot.

Time: the extraction readout

With dose and ratio fixed, shot time tells you what the grind is doing. The window is 25–30 seconds (illy's spec; a single runs 20–25). Fast, thin, blonde-early shots: grind finer. Slow, dark, dripping shots: grind coarser. This is the same sour-coarser/sweet-spot/bitter logic as every other method — see grind size vs extraction — but compressed into seconds, which is why espresso punishes stale beans and inconsistent grinders so hard.

The beginner's first week

1. Lock in dose (18 g) and yield (36 g). Do not change them for a week.
2. Grind fine enough that the shot takes 25–30 seconds; adjust one notch at a time.
3. Distribute and tamp level — channeling (water finding one path through the puck) mimics every other problem and fixes none of them.
4. Taste, then change exactly one variable. Sour → finer. Bitter → coarser. Both → check freshness and distribution.
5. Only after a week of repeatable shots, explore ratio: 1:1.5 for milk drinks, 1:2.5 for light roasts as straight shots.

Temperature and the rest

illy's 88–92°C is lower than filter-coffee temperatures because pressure does work heat otherwise would; an SCA-published survey of industry practice found most respondents brewing espresso in the classic 195–205°F band anyway, averaging about 200°F. Machine temperature is largely what it is at home — spend your attention on dose, ratio, grind and beans, and let the machine's thermostat do its job (context in temperature by roast). Fresh beans matter more here than anywhere: CO₂ from a too-fresh roast causes channeling, while staling beyond a month or so produces shots that no grind change rescues.

Related reading

• Ratios by method — espresso's 1:2 in context
• Moka pot guide — strong coffee without 9 bar
• Scale vs scoop — measurement at 0.1 g stakes
• SCA Golden Cup — the filter-side standard